1. Technical Field
The invention relates to a scanner. Particularly, the invention relates to a three-dimensional scanner.
2. Related Art
Along with progress of computer technology and development of multimedia technology, computers have gradually become indispensable tools in people's daily life, and rapid development of image processing technique leads to progress of computer peripheral image processors, for example, three-dimensional (3D) scanners.
Generally, a 3D scanner is an instrument used for detecting and analysing shapes (geometric structures), and appearance information (for example, color, surface reflectance, etc.) of objects or environment in the real world, and the collected data is usually used in 3D reconstruction calculation, so as to build digital models of physical objects in a virtual world. Theses digital models have a very wide range of application, and can be applied in, for example, industrial design, defect detection, reverse engineering, robot guidance, topography measurement, medical information, biological information, criminal identification, digital antique collection, film production, game creation material, 3D printing, etc.
A conventional 3D scanner generally uses at least two cameras to capture a plurality of color images of an object to be reconstructed, and image processing software is used to process the color images to construct a digital 3D model. Conceptually, such method is similar to that a human being deduces an image depth according to superposition of images sensed by the two eyes, and if a space between the cameras and focal lengths thereof are known, and the captured images can be successfully superposed, the depth information can be quickly deduced. Such method relies on effective correspondence analysis of image pixels, which is generally implemented by using a block matching method or an epipolar geometry algorithm, where a 3D vision method that applies two cameras is also referred to as a binocular method, and there is a trinocular method and other extending methods that apply more cameras. However, such 3D scanner is complicated in image processing and calculation for building a digital 3D model, and a cost thereof cannot be effectively reduced.